Journal Article

Type 1 dopamine receptor (D1R)-independent circadian food anticipatory activity in mice

Sidikpramana, Michael, Steele, Andrew D., Villa, Andrew P., Assali, Dina R., Falkenstein, Jeffrey

2021

Overview

Circadian rhythms are entrained by light and influenced by non-photic stimuli, such as feeding. The activity preceding scheduled mealtimes, food anticipatory activity (FAA), is elicited in rodents fed a limited amount at scheduled times. FAA is thought to be the output of an unidentified food entrained oscillator. Previous studies, using gene deletion and receptor pharmacology, implicated dopamine type receptor 1 (D1R) signaling in the dorsal striatum as necessary for FAA in mice. To further understand the role of D1R in promoting FAA, we utilized the Cre-lox system to create cell type-specific deletions of D1R, conditionally deleting D1R in GABA neurons using Vgat-ires-Cre line. This conditional deletion mutant had attenuated FAA, but the amount was higher than expected based on prior results using a constitutive knockout of D1R, D1R KO Drago . This result prompted us to re-test the original D1R KO Drago line, which expressed less FAA than controls, but only moderately so. To determine if genetic drift had diminished the effect of D1R deletion on FAA, we re-established the D1R KO Drago knockout line from cryopreserved samples. The reestablished D1R KO Drago-cryo had a clear impairment of FAA compared to controls, but still developed increased activity preceding mealtime across the 4 weeks of timed feeding. Finally, we tested a different deletion allele of D1R created by the Knockout Mouse Project. This line of D1R KO KOMP mice had a significant impairment in the acquisition of FAA, but eventually reached similar levels of premeal activity compared to controls after 4 weeks of timed feeding. Taken together, our results suggest that D1R signaling promotes FAA, but other dopamine receptors likely contribute to FAA given that mice lacking the D1 receptor still retain some FAA.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Animal behavior / Biology and Life Sciences / Carbohydrates / Caudate-putamen / Circadian rhythm / Circadian rhythms / Circuits / Critical components / Data analysis / Deoxyribonucleic acid / DNA / Dopamine / Dopamine D1 receptors / Dopamine receptors / Drug addiction / Editing / Engineering and Technology / Experiments / Food / Food habits / Laboratories / Locomotion / Medicine and Health Sciences / Metabolism / Motivation / Neostriatum / Neurons / Nucleus accumbens / Period 2 protein / Physical Sciences / Physiological aspects / Physiological research / Proteins / Psychological aspects / Reviews / Signaling / Social Sciences / Substantia nigra / Ventral tegmentum / Zeitgeber